1. Technical Field
The present invention relates to belts, and more particularly to fire-retardant belts, for example used in elevator systems.
2. Background Information
Conventional traction elevator systems have included a car, a counterweight, two or more ropes interconnecting the car and the counterweight, and a machine and a traction sheave to move the ropes. The ropes were conventionally formed of steel wires formed into strands, the strands then formed into cords, and the cords then formed into the rope.
Although conventional ropes have proven to be very reliable and cost effective, belts have been used in recent years as an alternative to the conventional ropes. Some belts have been designed with a plurality of steel cords covered by a thermoplastic jacket to suspend and/or lift the elevator car. Fire-retardant thermoplastic jacket compositions have been used in order to resist or minimize any burning of the thermoplastic jacket. It has been discovered, however, that even when using fire-retardant thermoplastic jacket compositions, fire spreads more rapidly along an narrow edge or corner of the jacket than along a broad, flat surface of the jacket. What is needed, therefore, is an improved belt directed toward this problem.